I suggest, dumb her. Find a more perfect woman! If both of you really love each other, then either one of you should not encourage one or the other to engage sex with other people. Personally, I feel that engaging sex with other people other than the one you love is totally a sin and is unforgivable to your other partner. Secondly, she say that you can have sex with anyone but just dont fall in love with them right? Well, LOVE is a mystical thing if you ask me. We, MEN have one poor habits. That is we love each and every beautiful ladies. Once you got hold of one, you want another. Its hard of not falling in love with other beautiful ladies. Because of that, self-endurance and mutual respect with your partner need to be stronger to overcome this habit. I am not really an open-minded person, more towards conservative man. But just here to offer my view. In fact, I am not married yet. As for your question on paid sex. Well, seeking prostitute is also a sin if you ask me. This shows you are not satisfied with your own gf or wife and are seeking others to release your please. If you love someone whole-heartly, say NO to prostitute. Devote yourselves fully to her. If your gf is mine, I will surely dumb her for this is not the kind of person I am looking for to be for the next part of my life.
Your being played with, she's like the totally detached independent "I do what I want" type of girl, and you are the devoted, loving, caring guy who just wants to settle down, those two dont mix..you are just going to get hurt, get a girl who will love you and really make you feel it. She clearly isnt.